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In this study, a three-rib intersecting composite diamond honeycomb structure is fabricated by interlocking technology. The mechanical properties of the composite interlocked diamond honeycomb (CIDH) and corresponding sandwich structure (CIDHSS) are experimentally tested. The stiffness, strength, and failure characteristics of CIDH and CIDHSS are analyzed. The results show that CIDH has better mechanical properties than the interlocked Kagome and square honeycombs. The edge effect limits the edge compressive strength and stiffness of CIDH. Debonding is the main failure mode that limits both bending and compressive strength of CIDHSS. The reinforced plate added to the edge effectively improves the anti-debonding ability. [ABSTRACT FROM AUTHOR]

The authors report an experimental investigation on square thin-walled energy absorbers with different topologies and materials. The material was steel SAE 1010 and aluminum AL 6160. Some samples non-filled and filled with polymeric material received patterned windows placed in opposite faces with specific dimensions: 20x20, 15x30, and 20x30 mm2. Quasi-static axial loading crushes hollow specimens and hybrid specimens filled with PET-G honeycomb. The core filling was printed using the FDM technique. The crashworthy ability of specimens was evaluated based on the specific energy absorption (SEA), load ratio (LR) and structural efficiency (η), which showed that windowed-filled specimens with 20x30 mm2 perform better. The maximum increase of SEA was 212%, LR decreased from 4.02 to 1.78 and η increased from 0.45 to 0.89 for steel energy absorbers and in the same manner, the values for aluminum specimens were 123%, 2.97 to 1.28 and 0.46 to 0.71. The effects of the patterned windows and their combination with the honeycomb core for both metallic materials show that such a topology improved the performance in two factors. The windows reduced the peak force, and the PET-G honeycomb furnished a smoothing to the region at the end of the fold formation, contributing to the crashworthy ability. Future work envisages experimental testing of the samples in dynamic tests. [ABSTRACT FROM AUTHOR]

This study presents a novel approach inspired by the hexagonal honeycomb structure found in nature, leveraging image processing algorithms to precisely define complex geometries in thermal systems. Hexagonal phase change material containers and thermally conductive fins were meticulously delineated, mirroring the intricate real-world designs of honeycombs. This innovative methodology not only streamlines setup processes but also enhances our understanding of melting dynamics within enclosures, highlighting the potential benefits of biomimetic design principles in engineering applications. Two distinct honeycomb structures were employed to investigate their impact on the melting process within cavities subject to heating from the left wall, with the remaining walls treated as adiabatic surfaces. The incorporation of a thermally conductive fin system within the enclosure significantly reduced the time required for a complete phase change, emphasizing the profound influence of fin systems on thermal design and performance. This enhancement in heat transfer dynamics makes fin systems advantageous for applications prioritizing precise temperature control and expedited phase change processes. Furthermore, the critical role of the fin system design was emphasized, influencing both the onset and location of the final point of melting. This underscores the importance of tailoring fin systems to specific applications to optimize their performance. Our study highlights the significant impact of the Rayleigh (Ra) number on the melting time in a cavity without fins, revealing a decrease from 6 to 0.4 as the Ra increased from 102 to 105; the introduction of a fin system uniformly reduced the melting time to Ste.Fo = 0.5, indicating fins' universal effectiveness in optimizing thermal dynamics and expediting the melting process. Moreover, the cavity angle was found to significantly affect the fluid fraction diagram in unfanned cavities but had minimal impact when fins were present, highlighting the stabilizing role of fins in mitigating gravitational effects during melting processes. These insights expand our understanding of cavity geometry and fin interactions in heat transfer, offering potential for enhanced thermal system designs in various engineering applications. Decreasing thermal conductivity (λ) by increasing the fin thickness can halve the melting time, but the accompanying disadvantages include a heavier system and reduced energy storage due to less phase change material, necessitating a careful balance in decision-making. [ABSTRACT FROM AUTHOR]

The cuttlebone is known for its ability to possess high specific stiffness, progressive failure and lightweight from the porous chambered structure. Inspired by the microstructural characteristics of cuttlebone and incorporating the wall gradient design, a series of double-asymmetric honeycombs were designed and processed by LPBF. Results indicated that bionic structural units with the junction design can maintain the integrity of the residual parts after local buckling and failure, improving the load-bearing capacity. The double-asymmetric honeycomb with gradation parameter a = 2/3 achieved a maximum specific compressive strength of 70.64 MPa cm3/g. As a decreases, there is an increase in specific energy absorption and a narrowing of the hysteresis loop. The as-build honeycomb had undergone stress-induced martensite transformation during compression. The dissipated mechanical energy (ME) decreased with the increasing cycle number and the decreasing a. The results provide design guidelines and process strategies for developing high-performance honeycombs. [ABSTRACT FROM AUTHOR]

In this paper, sorghum and reed, which possess light stem structures in nature, were selected as biomimetic prototypes. Based on their mechanical stability characteristics—the porous structure at the node feature and the porous feature in the outer skin— biomimetic optimization design, simulation, and experimental research on both the traditional hexagonal structure and a hexagonal honeycomb structure were carried out. According to the two types of straw microcell and chamber structure characteristics, as well as the cellular energy absorption structure for the bionic optimization design, 22 honeycomb structures in 6 categories were considered, including a corrugated cell wall bionic design, a modular cell design, a reinforcement plate structure, and a self-similar structure, as well as a porous cell wall structure and gradient structures of variable wall thickness. Among them, HTPC-3 (a combined honeycomb structure), HSHT (a self-similar honeycomb structure), and HBCT-257 (a radial gradient variable wall thickness honeycomb structure) had the best performance: their energy absorption was 41.06%, 17.84%, and 83.59% higher than that of HHT (the traditional hexagonal honeycomb decoupling unit), respectively. Compared with HHT (a traditional hexagon honeycomb decoupling unit), the specific energy absorption was increased by 39.98%, 17.24%, and 26.61%, respectively. Verification test analysis revealed that the combined honeycomb structure performed the best and that its specific energy absorption was 22.82% higher than that of the traditional hexagonal structure. [ABSTRACT FROM AUTHOR]

The shape memory alloy (SMA) can deform pseudo-plastically under external load, based on which a reusable impact energy absorption structure was designed. According to the classical SMA constitutive model, the finite element model for thin-wall structures was established, and the dynamic characteristics such as deformation modes and energy absorption of different forms of honeycomb structures under different impacting velocities, were analyzed, and the optimal energy absorption performance of the SMA structures was obtained. In addition, through comparison of the energy absorption performance of the SMA honeycomb with that of the aluminum honeycomb, the energy absorption of the SMA honeycomb with different structure configurations was different from that of the aluminum honeycomb under different-velocity impacts, with the optimal structure changes. The work provides a reference for the selection and design of the SMA honeycomb structures. [ABSTRACT FROM AUTHOR]

• A class of modified hexagonal honeycomb to realize pattern transformation. • Honeycomb's elastic constants are derived by theoretical energy analysis. • Honeycomb structures exhibit auxetic behavior after pattern transformation. • The cell/node of the honeycomb has a rotating behavior after pattern transformation. • The underlying mechanism of pattern transformation is revealed for honeycomb. Pattern transformation, as one of the special properties of mechanical metamaterials, is widely found in elastic porous structures and gradually expanding to honeycomb structures. Inspired by the higher-order flower-like buckling pattern of hexagonal honeycomb, and generalizing the geometry of structures that pattern transformation occurs under uniaxial compression, this paper proposes a Modified Hexagonal Honeycomb(MHH) structure by adjusting the thickness ratio α and the deflection extension angle θ of the cell wall to topologically reconstruct the honeycomb structure to initiate the first-order quasi-flower-like buckling pattern under uniaxial loading. Results show that the quasi-flower-like pattern transformation appears directly for the MHH structure under uniaxial compression, accompanied with a transition of the Poisson's ratio, from positive to negative. And the butterfly pattern, which appears for traditional hexagonal honeycomb only under biaxial loading, is also observed for the MHH under uniaxial compression. The relative size of the nodes among cell walls is believed to play a crucial role on the appearance of the pattern transformation of the honeycomb structure. This work has revealed the underlying physical mechanism for pattern transformation of honeycomb structures, and would also extend the application range of honeycomb structures to the design of elastic dampers, bending/torsion actuators, or robot drive joints. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis and characterization of modified NH 2 -MCM-41 for drug release. • Performance of modified NH 2 -MCM-41 nanoparticles improved compared to MCM-41. • Analysis of Adriamycin, Metformin and Naproxen drugs release. The aim of this work is the preparation and characterization of modified mesoporous silica NH 2 -MCM-41 (NM-41) nanoparticles (NPs) in comparison to MCM-41 (M−41) with the aim of obtaining a pH-sensitive system for controlled drug release (CDR) applicable in cancer treatment. Three drugs were used for CDR studies including Adriamycin, Metformin and Naproxen, and loaded onto the mesoporous silica. The samples were prepared and analyzed by solid characterization methods including FTIR, XRD, SEM, TEM, BET, and DSC analyses. The SEM images clearly showed the increase in surface porosity of NM-41 nanocarriers (NCs) compared to M−41 NCs. The CDR behavior of the obtained NCs was investigated at pH 1.5–3.5 (simulated gastric fluid media-SGF), pH 6 (simulated intestine fluid media-SIF) and pH 7.35–7.45 (simulated body fluid media-SBF). The results showed that the performance of modified NM-41 NPs improved compared to M−41, and the performance of modified NM-41 NPs at SIF and SBF pHs is much higher than SGF, which shows the success in the preparation of drug pH-sensitive NCs for CDR. The results of drug loading showed that the amount of Adriamycin, Metformin and Naproxen drugs in modified NM-41 NPs is significantly higher than M−41. Furthermore, survival studies were conducted for the prepared systems and the results showed good biocompatibility of the prepared drug delivery systems (DDS). [ABSTRACT FROM AUTHOR]

The battery-pack system of electric vehicles is prone to collide with low obstacles on the road, causing battery short circuits and even explosions. It poses a great safety threat to passengers and drivers. The honeycomb structure's high energy absorption and lightweight properties have made it a popular choice in the automotive industry. This paper designs different bio-inspired honeycomb structures to a battery-pack system of electric vehicles to improve the crashworthiness performance. The effects of different bio-inspired honeycomb structures on the crashworthiness of a battery-pack system during frontal impact are analyzed based on a nonlinear finite element model. First, the geometric parameters of seven different bio-inspired honeycomb individual units are described. The overall structure of the honeycomb is applied to a battery-pack system. Second, the nonlinear finite element model of a battery-pack system and honeycomb structures are established and verified. Then, collision simulations are conducted. The deformation and the maximum stress of a battery-pack's bottom shell are computed. The energy absorbed by the honeycomb structures during frontal impact are investigated. The results indicate that the proposed bio-inspired honeycomb structure mimicking grass stems improves the safety performance of battery-pack systems most. Finally, a parametric design is carried out on the bio-inspired honeycomb structure. The effects of wall thicknesses and the number of replacement hexagons on the crashworthiness performance are analyzed. The honeycomb structure preforms best when thickness is 1 mm and the number of replacement hexagons is 2 and 4. The optimized bio-inspired honeycomb structure reduces the deformation of the battery-pack' bottom shell by up to 30%, and maximum stress by 10%. • The deformation, maximum stress, and energy absorption are investigated. • The effects of seven bio-inspired honeycomb structures are analyzed. • Parametric design is carried out to further improve the crashworthiness performance. • The deformation of the bottom shell can be reduced by up to 30%. [ABSTRACT FROM AUTHOR]

• A honeycomb-structured superhydrophobic coating is prepared. • The coating exhibited a high visible light transmittance (90.0%). • By regulating structure, the haze of the coating can be adjusted (8.9%-54.1%). • The coating has excellent mechanical abrasion and weathering resistance. Transparent superhydrophobic coatings have excellent self-cleaning performance and are particularly suitable for applications in the fields of outdoor photovoltaic displays, solar power generation, and windows. However, the micro-nanostructures required for superhydrophobic coatings make them poor abrasion-resistant and foggy, and hence transparent superhydrophobic coatings with good practicality still remain great challenging. Here, we report honeycomb-structured coatings simultaneously with high transparency, abrasion-resistance and superhydrophobicity by fabrication of honeycomb epoxy resin structure via PDMS template method and subsequent spraying of hydrophobic SiO 2 nanoparticles. The coatings with different honeycomb structures exhibit average transmittance of 90.0 %, and the haze in the range of 8.9–54.1 %. Both the honeycomb structure formed by hard epoxy resin and strong adhesion of hydrophobic SiO 2 nanoparticles enable the coatings to maintain superhydrophobicity after harsh mechanical abrasion and weathering. [ABSTRACT FROM AUTHOR]

The natural beesʼ honeycombs maintain long-term structural stability in harsh environments, employing a highly material-efficient approach. However, the reasons remain somewhat ambiguous. To clarify the stabilization mechanism and investigate quasi-static compression responses of double-layer ordered cellular structures, honeycomb, Tóth and single-layer cellular structures with a relative density (ρ r) of 25.84 % were fabricated using 3D printing technology. Then, quasi-static compression experiments in three directions were conducted. Further, a numerical study was conducted to uncover the stabilization mechanism and effect of ρ r on compressive behaviors. Results revealed that the stabilization mechanism was mainly attributed to bearing load priority of intermediate layer and its inhibition on formation of plastic hinges. A relative density of 5.17 % served as a transition point for deformation mode, beyond which honeycomb and Tóth structures exhibited stronger in-plane compressive strength at expense of less sacrificed out-of-plane compressive strength, below which they both exhibited more stable compressive curves compared to single-layer cellular structures, which were favorable for energy absorption. This study clarifies the stability mechanism of beesʼ honeycombs and addresses the lack on compression behaviors of double-layer ordered cellular structures. Moreover, it introduces two available bionic structures with controllable deformation modes to expand the application of single-layer cellular structures. [ABSTRACT FROM AUTHOR]

• Combining ML and FE methods to accelerate the design process of honeycomb structures. • Using 2D unit cell surrogate 3D honeycomb structures. • CDAE with a pixelation strategy is proposed to manage FE data. • LSTM uses latent features and external loads to predict structural dynamic responses. In this study, a novel framework was presented for accelerating the prediction of the mechanical response of honeycomb structures under dynamic crushing, using 2D cells to surrogate 3D honeycomb structures by machine learning (ML). The sizes of different honeycomb structures were designed and the necessary training data obtained through finite element (FE) simulations, but without using any explicit design parameters of the honeycomb cells in the ML model. A pixelization method of FE model was proposed to separate the complete cell structure from the honeycomb FE grid data and convert it into a matching pixel map. FE data was structuralized while reducing the large amount of computational power consumed in identifying complex array structures. Unsupervised automatic extraction of low-dimensional features of pixel maps was performed using a convolutional denoising autoencoder (CDAE). The crushing velocity and the extracted latent features were used as the input of the long-short term memory (LSTM) network to predict the crushing deformation and stress-strain curve of the honeycomb structure under different dynamic loading. Results showed that the constructed ML model could describe the dynamic crushing response behavior. Compared with the traditional FE method, the prediction model was 4.45 × 103 and 1.05 × 103 times faster in predicting the stress-strain and structural deformation response, respectively. The mechanical response prediction model provided a method for rapidly evaluating the dynamic mechanical response behavior of similar periodic array structures using FE model data, which could be beneficial for the design and development of equipment based on bionic structures. [ABSTRACT FROM AUTHOR]

Hydrogen production from biomass is an efficient and clean utilization way for renewable energy to significantly alleviate the energy crisis. In order to improve the biomass conversion efficiency, a device combining honeycomb structure wood and inert porous pellets was proposed, and the combustion characteristics of honeycomb wood was studied with different biomass species and pore structures. The results indicated that softwood had the higher syngas yield compared with hardwood, and the hydrogen yield was up to 9.0 %. The increasing of inlet air velocity improved combustion temperature, but it was not conducive to syngas production. In addition, circle shape structure showed the stable combustion rate and the high conversion efficiency due to the uniform pore distribution. With the increasing of pore number, outlet temperature and hydrogen production increased first and then decreased. Moreover, syngas yield improved as the pore diameter increased and the maximum hydrogen growth rate reached 256 %. Meanwhile, the co-combustion mechanism of honeycomb wood and inert pellets was revealed, and the efficient realization of heat-hydrogen coproduction had practical guiding significance for optimizing the energy structure. [ABSTRACT FROM AUTHOR]